The problem is that the folders /etc/cron.* do not exist. I created /etc/cron.daily folder, but cron doesn't check the scripts in that folder what could I do so that the cron daemon check runs cron.daily on a daily basis?
BTW, I though of adding an entry to the crontab file but I don't want that.
Also, I created a file called /etc/cron.allow to allow postgres to have it owns cronjobs and that worked.